In the field of microfabrication such as production of integrated circuit devices, a fine resist pattern may be formed by forming a resist film on a substrate using a resin composition that includes a polymer that contains an acid-labile group that dissociates due to an acid, exposing the resist film by applying short-wavelength radiation (e.g., excimer laser light) to the resist film via a mask pattern, and removing the exposed area using an alkaline developer. This process may utilize a chemically-amplified resist that includes a photoacid generator that generates an acid upon irradiation (exposure), and exhibits improved sensitivity due to the acid.
In recent years, liquid immersion lithography that exposes a resist film in a state in which an immersion liquid (e.g., purified water or fluorine-containing inert liquid) is provided between the lens and the resist film has become widespread as a method that can form a fine resist pattern having a line width of about 60 nm or less. The numerical aperture (NA) of the lens can be increased when using liquid immersion lithography. Moreover, the depth of focus decreases to only a small extent, and high resolution can be obtained even when increasing the NA of the lens.
It is preferable that the resist film used for liquid immersion lithography exhibit high surface hydrophobicity during liquid immersion lithography from the viewpoint of improving the scan speed resistance, and suppressing elution of the resist film composition into the immersion liquid, occurrence of defects due to droplets that remain on the surface of the film, and the like. In recent years, a method that improves the hydrophobicity of the surface of the resist film has been studied, and a resin composition that contains a fluorine-containing polymer that exhibits high hydrophobicity has been proposed (see Japanese Patent Application Publication (KOKAI) No. 2010-32994 and WO2007/116664, for example).
Japanese Patent Application Publication (KOKAI) No. 2010-32994 discloses a resin composition that includes a fluorine-containing polymer that includes a fluoroalkyl group as an alkali-labile group that dissociates under alkaline conditions. The fluoroalkyl group dissociates during alkali development via a reaction with the developer to produce a carboxylic acid, so that the surface of the resist film exhibits hydrophilicity. WO2007/116664 discloses a resin composition that includes a fluorine-containing polymer that contains an acid-labile group. The acid-labile group dissociates upon exposure to produce a polar group, so that the fluorine-containing polymer present in the exposed area exhibits improved solubility in the developer.
According to the invention, a radiation-sensitive resin composition includes (A) a polymer that includes a repeating unit (a1) and a fluorine atom, and (B) a photoacid generator, the repeating unit (a1) including a group shown by any of formulas (1-1) to (1-3),
wherein RP represents a monovalent organic group, Z1 represents a carbon atom, Z2 represents a trivalent group that forms a cyclic hydrocarbon group together with Z1, Q0 in the formula (1-1) individually represent a hydrogen atom or a monovalent group, provided that at least one of Q0 represents a monovalent organic group that includes an electron-withdrawing group, Q0 in the formula (1-3) represents a monovalent organic group that includes an electron-withdrawing group, provided that a case where all of Q0 in the formula (1-1) represent a fluorine atom or a fluorine-substituted hydrocarbon group is excluded, and “*” indicates a bonding hand.
The composition makes it possible to form a resist film that can suppress occurrence of development defects as much as possible.
According to the invention, a polymer includes a fluorine atom and at least one repeating unit among repeating units shown by the following formulas (P-1) to (P-3).
wherein L represents a (b+1)-valent linking group, LB represents a single bond or a (b+1)-valent linking group, RP represents a monovalent organic group, Z1 represents a carbon atom, Z2 represents a trivalent group that forms a cyclic hydrocarbon group together with Z1, Q0 in the formula (P-1) individually represent a hydrogen atom or a monovalent group, provided that at least one of Q0 represents a monovalent organic group that includes an electron-withdrawing group, Q0 in the formula (P-3) represents a monovalent organic group that includes an electron-withdrawing group, provided that a case where all of Q0 in the formula (P-1) represent a fluorine atom or a fluorine-substituted hydrocarbon group is excluded, and b in the formulas (P-1) and (P-2) is an integer from 1 to 5, provided that a plurality of RP and a plurality of Q0 may respectively be either the same or different when b is an integer from 2 to 5, b in the formula (P-3) is 1 when LB represents a single bond, and is an integer from 1 to 5 when LB does not represent a single bond, provided that a plurality of RP, a plurality of Z2, and a plurality of Q0 may respectively be either the same or different when b is an integer from 2 to 5.
RM represents any of groups shown by the following formulas.
wherein RM1 represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, or a fluoroalkyl group having 1 to 5 carbon atoms, RE represents a substituent, d is an integer from 0 to 4, provided that a plurality of RE may be either the same or different when d is an integer from 2 to 4, e is 0 or 1, and “*1” indicates a bonding hand bonded to L or LB.
According to the invention, a compound includes a fluorine atom and is shown by any of the following formulas (M-1) to (M-3).
wherein L represents a (b+1)-valent linking group, LB represents a single bond or a (b+1)-valent linking group, RT represents a hydrogen atom or a monovalent organic group, Z1 represents a carbon atom, Z2 represents a trivalent group that forms a cyclic hydrocarbon group together with Z1, Q0 in the formula (M-1) individually represent a hydrogen atom or a monovalent group, provided that at least one of Q0 represents a monovalent organic group that includes an electron-withdrawing group, Q0 in the formula (M-3) represents a monovalent organic group that includes an electron-withdrawing group, provided that a case where all of Q0 in the formula (M-1) represent a fluorine atom or a fluorine-substituted hydrocarbon group is excluded, b in the formulas (M-1) and (M-2) is an integer from 1 to 5, provided that a plurality of RT and a plurality of Q0 may respectively be either the same or different when b is an integer from 2 to 5, b in the formula (M-3) is 1 when LB represents a single bond, and is an integer from 1 to 5 when LB does not represent a single bond, provided that a plurality of RT, a plurality of Z2, and a plurality of Q0 may respectively be either the same or different when b is an integer from 2 to 5.
R0 represents any of groups shown by the following formulas.
wherein RM1 represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, or a fluoroalkyl group having 1 to 5 carbon atoms, RE represents a substituent, d is an integer from 0 to 4, provided that a plurality of RE may be either the same or different when d is an integer from 2 to 4, e is 0 or 1, and “*3” indicates a bonding hand bonded to L or LB.